Add fuzz tests for obfuscated2

mtglib/internal/obfuscated2/client_handshake_fuzz_internal_test.go

+package obfuscated2
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+var FuzzClientHandshakeSecret = []byte{1,2,3}
+
+func FuzzClientHandshake(f *testing.F) {
+	f.Add([]byte{1,2,3})
+
+	f.Fuzz(func(t *testing.T, frame []byte) {
+		data := bytes.NewReader(frame)
+
+		if _, _, _, err := ClientHandshake(FuzzClientHandshakeSecret, data); err != nil {
+			return
+		}
+
+		handshake := clientHandhakeFrame{}
+		require.Len(t, frame, handshakeFrameLen)
+
+		copy(handshake.data[:], frame)
+
+		decryptor := handshake.decryptor(FuzzClientHandshakeSecret)
+		decryptor.XORKeyStream(handshake.data[:], handshake.data[:])
+
+		require.Equal(t, handshakeConnectionType, handshake.connectionType())
+	})
+}

mtglib/internal/obfuscated2/init_test.go

 package obfuscated2_test
 
 import (
+	"bytes"
+	"crypto/aes"
+	"crypto/cipher"
 	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"os"
 	"path/filepath"
 	"strings"
+	"testing"
+
+	"github.com/9seconds/mtg/v2/internal/testlib"
+	"github.com/9seconds/mtg/v2/mtglib/internal/obfuscated2"
+	"github.com/stretchr/testify/require"
 )
 
 type snapshotBytes struct {
 	snapshots map[string]*Obfuscated2Snapshot
 }
 
+type ServerHandshakeTestData struct {
+	connMock *testlib.EssentialsConnMock
+
+	proxyConn obfuscated2.Conn
+	encryptor cipher.Stream
+	decryptor cipher.Stream
+}
+
 func (suite *SnapshotTestSuite) IngestSnapshots(dirname, namePrefix string) error {
 	suite.snapshots = map[string]*Obfuscated2Snapshot{}
 
 
 	return nil
 }
+
+func NewServerHandshakeTestData(t *testing.T) ServerHandshakeTestData {
+	buf := &bytes.Buffer{}
+	connMock := &testlib.EssentialsConnMock{}
+
+	handshakeEnc, handshakeDec, err := obfuscated2.ServerHandshake(buf)
+	require.NoError(t, err)
+
+	serverEncrypted := buf.Bytes()
+	decBlock, _ := aes.NewCipher(serverEncrypted[8 : 8+32])
+	decryptor := cipher.NewCTR(decBlock, serverEncrypted[8+32:8+32+16])
+
+	serverDecrypted := make([]byte, len(serverEncrypted))
+	decryptor.XORKeyStream(serverDecrypted, serverEncrypted)
+
+	require.Equal(t, "3d3d3Q",
+		base64.RawStdEncoding.EncodeToString(serverDecrypted[8+32+16:8+32+16+4]))
+
+	serverEncryptedReverted := make([]byte, len(serverEncrypted))
+
+	for i := 0; i < 32+16; i++ {
+		serverEncryptedReverted[8+i] = serverEncrypted[8+32+16-1-i]
+	}
+
+	encBlock, _ := aes.NewCipher(serverEncryptedReverted[8 : 8+32])
+	encryptor := cipher.NewCTR(encBlock, serverEncryptedReverted[8+32:8+32+16])
+
+	return ServerHandshakeTestData{
+		connMock: connMock,
+		proxyConn: obfuscated2.Conn{
+			Conn: connMock,
+			Encryptor: handshakeEnc,
+			Decryptor: handshakeDec,
+		},
+		encryptor: encryptor,
+		decryptor: decryptor,
+	}
+}

mtglib/internal/obfuscated2/server_handshake_fuzz_internal_test.go

+package obfuscated2
+
+import (
+	"encoding/binary"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func FuzzServerGenerateHandshakeFrame(f *testing.F) {
+	f.Fuzz(func(t *testing.T, arg int) {
+		frame := generateServerHanshakeFrame()
+
+		assert.NotEqualValues(t, 0xef, frame.data[0])
+
+		firstBytes := binary.LittleEndian.Uint32(frame.data[:4])
+		assert.NotEqualValues(t, 0x44414548, firstBytes)
+		assert.NotEqualValues(t, 0x54534f50, firstBytes)
+		assert.NotEqualValues(t, 0x20544547, firstBytes)
+		assert.NotEqualValues(t, 0x4954504f, firstBytes)
+		assert.NotEqualValues(t, 0xeeeeeeee, firstBytes)
+
+		assert.NotEqualValues(
+			t,
+			0,
+			frame.data[4] | frame.data[5] | frame.data[6] | frame.data[7])
+
+		assert.Equal(t, handshakeConnectionType, frame.connectionType())
+	})
+}

mtglib/internal/obfuscated2/server_handshake_fuzz_test.go

+package obfuscated2_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/mock"
+)
+
+func FuzzServerSend(f *testing.F) {
+	f.Add([]byte{1,2,3,4,5})
+
+	f.Fuzz(func(t *testing.T, data []byte) {
+		handshakeData := NewServerHandshakeTestData(t)
+
+		handshakeData.connMock.
+			On("Write", mock.Anything).
+			Return(len(data), nil).
+			Once().
+			Run(func(args mock.Arguments) {
+				message := make([]byte, len(data))
+				handshakeData.decryptor.XORKeyStream(message, args.Get(0).([]byte))
+				assert.Equal(t, message, data)
+			})
+
+		n, err := handshakeData.proxyConn.Write(data)
+
+		assert.EqualValues(t, len(data), n)
+		assert.NoError(t, err)
+		handshakeData.connMock.AssertExpectations(t)
+	})
+}
+
+func FuzzServerReceive(f *testing.F) {
+	f.Add([]byte{1,2,3,4,5})
+
+	f.Fuzz(func(t *testing.T, data []byte) {
+		handshakeData := NewServerHandshakeTestData(t)
+		buffer := make([]byte, len(data))
+
+		handshakeData.connMock.
+			On("Read", mock.Anything).
+			Return(len(data), nil).
+			Once().
+			Run(func(args mock.Arguments) {
+				message := make([]byte, len(data))
+				handshakeData.encryptor.XORKeyStream(message, data)
+				copy(args.Get(0).([]byte), message)
+			})
+
+		n, err := handshakeData.proxyConn.Read(buffer)
+
+		assert.EqualValues(t, len(data), n)
+		assert.NoError(t, err)
+		assert.Equal(t, data, buffer)
+		handshakeData.connMock.AssertExpectations(t)
+	})
+}

mtglib/internal/obfuscated2/server_handshake_test.go

 package obfuscated2_test
 
 import (
-	"bytes"
-	"crypto/aes"
-	"crypto/cipher"
-	"encoding/base64"
 	"testing"
 
-	"github.com/9seconds/mtg/v2/internal/testlib"
-	"github.com/9seconds/mtg/v2/mtglib/internal/obfuscated2"
 	"github.com/stretchr/testify/mock"
 	"github.com/stretchr/testify/suite"
 )
 type ServerHandshakeTestSuite struct {
 	suite.Suite
 
-	connMock  *testlib.EssentialsConnMock
-	proxyConn obfuscated2.Conn
-	encryptor cipher.Stream
-	decryptor cipher.Stream
+	data ServerHandshakeTestData
 }
 
 func (suite *ServerHandshakeTestSuite) SetupTest() {
-	buf := &bytes.Buffer{}
-	suite.connMock = &testlib.EssentialsConnMock{}
-
-	encryptor, decryptor, err := obfuscated2.ServerHandshake(buf)
-	suite.NoError(err)
-
-	suite.proxyConn = obfuscated2.Conn{
-		Conn:      suite.connMock,
-		Encryptor: encryptor,
-		Decryptor: decryptor,
-	}
-
-	serverEncrypted := buf.Bytes()
-
-	decBlock, _ := aes.NewCipher(serverEncrypted[8 : 8+32])
-	suite.decryptor = cipher.NewCTR(decBlock, serverEncrypted[8+32:8+32+16])
-
-	serverDecrypted := make([]byte, len(serverEncrypted))
-	suite.decryptor.XORKeyStream(serverDecrypted, serverEncrypted)
-
-	suite.Equal("3d3d3Q",
-		base64.RawStdEncoding.EncodeToString(serverDecrypted[8+32+16:8+32+16+4]))
-
-	serverEncryptedReverted := make([]byte, len(serverEncrypted))
-
-	for i := 0; i < 32+16; i++ {
-		serverEncryptedReverted[8+i] = serverEncrypted[8+32+16-1-i]
-	}
-
-	encBlock, _ := aes.NewCipher(serverEncryptedReverted[8 : 8+32])
-	suite.encryptor = cipher.NewCTR(encBlock, serverEncryptedReverted[8+32:8+32+16])
+	suite.data = NewServerHandshakeTestData(suite.T())
 }
 
 func (suite *ServerHandshakeTestSuite) TearDownTest() {
-	suite.connMock.AssertExpectations(suite.T())
+	suite.data.connMock.AssertExpectations(suite.T())
 }
 
 func (suite *ServerHandshakeTestSuite) TestSendToTelegram() {
 	messageToTelegram := []byte{10, 11, 12, 13, 14, 'a'}
 
-	suite.connMock.
+	suite.data.connMock.
 		On("Write", mock.Anything).
 		Return(len(messageToTelegram), nil).
 		Once().
 		Run(func(args mock.Arguments) {
 			message := make([]byte, len(messageToTelegram))
-			suite.decryptor.XORKeyStream(message, args.Get(0).([]byte)) // nolint: forcetypeassert
+			suite.data.decryptor.XORKeyStream(message, args.Get(0).([]byte)) // nolint: forcetypeassert
 			suite.Equal(messageToTelegram, message)
 		})
 
-	n, err := suite.proxyConn.Write(messageToTelegram)
+	n, err := suite.data.proxyConn.Write(messageToTelegram)
 	suite.EqualValues(len(messageToTelegram), n)
 	suite.NoError(err)
 }
 	messageFromTelegram := []byte{10, 11, 12, 13, 14, 'a'}
 	buffer := make([]byte, len(messageFromTelegram))
 
-	suite.connMock.
+	suite.data.connMock.
 		On("Read", mock.Anything).
 		Return(len(messageFromTelegram), nil).
 		Once().
 		Run(func(args mock.Arguments) {
 			message := make([]byte, len(messageFromTelegram))
-			suite.encryptor.XORKeyStream(message, messageFromTelegram)
+			suite.data.encryptor.XORKeyStream(message, messageFromTelegram)
 			copy(args.Get(0).([]byte), message) // nolint: forcetypeassert
 		})
 
-	n, err := suite.proxyConn.Read(buffer)
+	n, err := suite.data.proxyConn.Read(buffer)
 	suite.EqualValues(len(messageFromTelegram), n)
 	suite.NoError(err)
 	suite.Equal(messageFromTelegram, buffer)